Simultaneous production of proteases and antioxidant biopeptides by solid-state fermentation

Usually, biopeptides and proteases are bioproducts produced in separate processes. However, through solid-state fermentation, they can be produced simultaneously, using agroindustrial by-products as substrates, reducing the environmental pollution and contributing to a circular bioeconomy. We aimed at the simultaneous production of proteases and biopeptides, using Aspergillus niger grown in soy bran and soy husk (70 : 30). The variables pH, moisture and nitrogen concentration were studied using Full Factorial Design 23. The best and simultaneous production of the biocompounds was obtained at pH 7, 50% moisture and 0.5% sodium nitrate as a nitrogen source, with 677 U g−1 proteases and 4154 μg mL−1 soluble proteins in 48 h, and an antioxidant activity of 2875.6 (mg mL−1 of Trolox equivalents) in 96 h of fermentation, with productivity confirmed in a double production scale. The production of these two biocompounds simultaneously in SSF has never been reported in the literature, thus highlighting the novelty and importance of this work.